The World Health Organization (WHO) recently prioritized the development of an international set of guidelines for the prevention of surgical site infection (SSI). Surgical site infections remain one of the most common healthcare associated infections and are a substantial burden to the healthcare system in addition to being a significant source of patient morbidity and mortality. The WHO guidelines provide evidence-based recommendations on preoperative (Part 1), intraoperative and postoperative measures (Part 2) for the prevention of SSIs.1,2 I reviewed preoperative measures for the prevention of SSI that are applicable to foot and ankle surgery in my last DPM Blog and one should read that in conjunction with this review of the new WHO recommendations of intraoperative and postoperative measures of the prevention of SSI.3
Part 2 of the new WHO recommendations provides 16 intraoperative and postoperative measures, 15 of which are relevant to foot and ankle surgeons to prevent surgical site infections.2 These evidence-based and expert consensus-based recommendations were developed with a global perspective and aim to balance benefits, harms, evidence quality, cost, resource use and patient values and preferences. The following are the WHO recommended intraoperative and postoperative measures for the prevention of SSI:2
Recommendation 1: Adult patients undergoing general anesthesia with endotracheal intubation should receive an 80 percent fraction of inspired oxygen (80% FiO2) intraoperatively and, if possible, in the immediate postoperative period for two to six hours. Neutrophils are the primary defense against SSI and their oxidative power requires the availability of molecular oxygen, which is highly dependent on the oxygen partial pressure of local tissue.4,5 Numerous studies have shown that the incidence of SSI is inversely related to tissue oxygen partial pressure during and for several hours following surgery.6-9 The WHO preformed a systematic review to assess the effect of perioperative high (80%) FiO2 in comparison to standard (30 to 35%) FiO2 for the prevention of SSI and found that higher perioperative FiO2 resulted in a reduced incidence of SSI.2
Recommendation 2: Maintain normothermia with the use of warming devices in the operating room during surgical procedures. There are numerous risks associated with intraoperative hypothermia including myocardial ischemia, prolongation of drug effects, bleeding diatheses, decreased skin integrity, increased length of hospital stay and increased incidence of SSI.10 Numerous modalities have emerged to reduce the incidence of intraoperative hypothermia with forced air warming being the most efficient at maintaining normothermia.11 Regardless of the warming method used, the WHO meta-analysis found perioperative body warming to be associated with a significantly reduced risk of SSI.2
Recommendation 3: Use intensive protocols to maintain perioperative blood glucose control. Hyperglycemia is associated with an increase risk of SSI in both diabetic and non-diabetic patients.12-14 The WHO meta-analysis found intensive protocols for perioperative blood glucose control were effective in reducing the risk of SSI in both patients with and without diabetes. There remains a lot of heterogeneity among protocols for perioperative blood glucose control but common features among these protocols that have been found to reduce the risk of SSI include the use of intensive blood glucose control both intraoperative and postoperatively, and maintaining blood glucose below 150 mg/dL.2
Recommendation 4: Use goal-directed fluid therapy (GDFT) intraoperatively to maintain adequate circulating volume. Sufficient intravascular volume is required to maintain adequate tissue perfusion and oxygenation, which has been shown to decrease the risk of SSI.15 Goal-directed fluid therapy is the administration of fluids and inotropic drugs with titration based on hemodynamic monitoring.16 The WHO meta-analysis found that intra-operative and post-operative, goal-directed fluid therapy was significantly associated with a lower incidence of SSI in comparison to standard intraoperative and postoperative fluid management.2
Recommendation 5 and 6: Use sterile, disposable non-woven or sterile reusable drapes and surgical gowns during surgical procedures for the prevention of SSI. Do not use plastic adhesive incise drapes with or without antimicrobial properties. While non-woven sterile disposable drapes are in standard use in most operating rooms in the United States, sterile woven reusable drapes remain in use in some rural areas and in numerous underdeveloped countries. The WHO meta-analysis showed no difference in the SSI risk with the use of sterile reusable or sterile disposable drapes.2 Research has not shown both iodine-impregnated adhesive incise drapes and non-impregnated adhesive incise drapes to lower SSI risk, and are thus a source of unnecessary cost.2
Recommendation 7 reviews the use of wound-protector devices in abdominal surgery and is not applicable to foot and ankle surgery.
Recommendations 8 and 9: Irrigate incisional wounds with an aqueous povidone-iodine solution before closure, particularly in clean and clean-contaminated wounds, in order to reduce SSI. Do not do antibiotic incisional wound irrigation before closure and there is insufficient evidence to recommend for or against saline irrigation of incisional wounds to prevent SSI. Wound irrigation is a common intraoperative practice that research has shown to reduce the incidence of SSI by several mechanisms, including hydration of the wound bed, removing debris, improving visualization of the incisional wound prior to closure and decreasing the bioburden.17
Clinicians have employed numerous wound irrigation techniques to reduce SSI. These techniques include saline irrigation, pulse pressure or forced saline irrigation, aqueous povidone-iodine solution irrigation and antibiotic irrigation. The WHO meta-analysis found that both saline irrigation, applied with pulse-pressure or force, and aqueous povidone-iodine solution irrigation of incisional wounds reduced the incidence of SSI in both clean and clean contaminated surgical wounds.2,18-20 Given the lack of evidence showing decreased SSI rates with the use of antibiotic incisional wound irrigation and the risk of developing antimicrobial resistance, the WHO expert panel recommends against this irrigation technique. With the cost and waste associated with pulse-pressure irrigation devices, aqueous povidone-iodine solution incisional wound irrigation is preferred.
Recommendation 10: Use prophylactic negative pressure wound therapy (NPWT) on high-risk, primarily closed surgical incisions for the prevention of SSI when resources are available. Negative pressure wound therapy aids wound healing in several ways including promoting angiogenesis and granulation tissue, removing drainage, promoting cell division, decreasing edema and improving circulation.21 By improving circulation, NPWT increases oxygenation and infection resistance. Prophylactic application of NPWT in primarily closed wounds can help to prevent SSI. The WHO meta-analysis showed that prophylactic NPWT significantly reduced the risk of SSI in comparison to conventional postoperative wound dressings.2 The greatest effect of prophylactic NPWT occurred in abdominal and cardiac surgery, and in clean and clean contaminated wounds. WHO recommends using prophylactic NPWT in conditions including poor tissue perfusion, soft tissue damage, bleeding/hematoma, dead space and wound contamination.
Recommendation 11: One should use antimicrobial triclosan-coated sutures to reduce the risk of SSI, regardless of surgery type. Triclosan is an antimicrobial agent that exhibits broad-spectrum activity against both gram-negative and gram-positive bacteria. Triclosan-coated sutures have been designed to reduce the incidence of SSIs. In vitro, animal studies and clinical studies have confirmed the antimicrobial effect of triclosan sutures.22-24 The WHO meta-analysis showed that antimicrobial sutures have a significant effect in reducing SSI in surgical patients in comparison to non-coated sutures. The effect of antimicrobial-coated sutures in reducing SSI was independent of suture type (braided or monofilament), wound contamination classification (clean or clean contaminated) or surgery type. The WHO recommends using antimicrobial triclosan suture for all surgical incisions to reduce the risk of SSI.
Recommendation 12: Do not use laminar air ventilation systems to reduce SSI risk in total joint arthroplasty surgery. Laminar airflow systems were designed to reduce contamination in high-risk surgeries by passing fresh air in one direction at a steady velocity to create a zone in the operating room that drives out aerosols and particles.25 In contrast, conventional operating room ventilation systems pass turbulent airflow through the room to homogenize fresh air, aerosols and particles. Laminar airflow systems have frequently been used in high-risk surgical cases such as instrumented spine and orthopedic implant surgery. The disadvantage of laminar airflow systems is the cost of installation and maintenance. The WHO meta-analysis showed no significant difference in the incidence of SSI with conventional versus laminar airflow ventilation.2 Given the cost of laminar airflow, its use is not recommended.
Recommendation 13 and 14: Antibiotic prophylaxis should not continue while wound drains are in place. Remove wound drains as soon as clinically indicated. There are risks and benefits with the use of wound drains. Drains remove blood and body fluids, decreasing the risk of hematoma/seroma formation. However, drains can serve as a conduit for infection and can delay wound healing.26,27 At many institutions, it is common practice to continue prophylactic antibiotics until removing surgical drains but this practice raises the concern of developing antimicrobial resistance.
The WHO meta-analysis showed that prolonged antibiotic prophylaxis in the presence of a wound drain did not reduce the incidence of SSI.2 There remains a limited amount of data examining early (one to five days) versus late (six-plus days) drain removal. The WHO meta-analysis showed no significant difference between early versus late drain removal but the researchers felt there was insufficient evidence to clearly identify optimal timing for drain removal.2
Reference 15: Standard wound dressings are preferable over advanced wound dressings for the prevention of SSI in primarily closed surgical wounds. Numerous types of advanced wound dressings exist but recent Cochrane reviews show no benefit of these dressings in reducing SSI.28,29 Additionally, the recent WHO meta-analysis did not show any significant benefit in the use of advanced surgical site dressings over conventional dressings in reducing SSI.2
Reference 16: Prophylactic antibiotic use should not continue following the completion of the surgical procedure for the purpose of reducing incidence of SSI. While research has repeatedly shown the administration of prophylactic antibiotics to reduce the incidence of SSI, the duration of administration for surgical antibiotic prophylaxis has not been clearly identified.30-32 Prolonged administration of surgical antibiotic prophylaxis increases the risk of developing antimicrobial resistant organisms but despite this, many providers continue surgical antibiotic prophylaxis for 24 hours or longer following surgery in an effort to reduce the risk of SSI. The WHO meta-analysis found that prolonged surgical antibiotic prophylaxis provided no greater benefit than single-dose antibiotic prophylaxis in reducing the incidence of SSIs.
These new recommendations provided by the WHO provide a much needed, uniform set of evidence-based measures to reduce SSI. Given the significant morbidity, mortality and cost associated with SSI, I highly recommend following these recommendations to reduce the incidence of SSI.
1. Allegranzi B, Bischoff P, de Jonge S, et al. New WHO recommendations on preoperative measures for surgical site infection prevention: an evidence-based global perspective. Lancet Infect Dis. 2016; 16(12):e276–e287.
2. Allegranzi B, Zayed B, Bischoff P, et al. New WHO recommendations on intraoperative and postoperative measures for surgical site infection prevention: an evidence-based global perspective. Lancet Infect Dis. 2016; 16(12):e288–e303.
3. Hoffman K. What the new WHO recommendations emphasize on preoperative measures for preventing surgical site infection. Podiatry Today DPM Blog. Available at http://www.podiatrytoday.com/blogged/what-new-who-recommendations-emphasize-preoperative-measures-preventing-surgical-site . Published Dec. 5, 2016.
4. Qadan M, Battista C, Gardner SA, Anderson G, Akca O, Polk HC, Jr. Oxygen and surgical site infection: a study of underlying immunologic mechanisms. Anesthesiology. 2010;113(2):369-377.
5. Allen DB, Maguire JJ, Mahdavian M, et al. Wound hypoxia and acidosis limit neutrophil bacterial killing mechanisms. Arch Surg. 1997;132(9):991-996.
6. Hopf HW, Hunt TK, West JM, et al. Wound tissue oxygen tension predicts the risk of wound infection in surgical patients. Arch Surg. 1997;132(9):997-1004; discussion 1005.
7. Knighton DR, Halliday B, Hunt TK. Oxygen as an antibiotic. The effect of inspired oxygen on infection. Arch Surg. 1984;119(2):199-204.
8. Govinda R, Kasuya Y, Bala E, et al. Early postoperative subcutaneous tissue oxygen predicts surgical site infection. Anesth Analg. 2010;111(4):946-952.
9. Abdelmalak BB, Cata JP, Bonilla A, et al. Intraoperative tissue oxygenation and postoperative outcomes after major non-cardiac surgery: an observational study. Br J Anaesth. 2013;110(2):241-249.
10. Hart SR, Bordes B, Hart J, Corsino D, Harmon D. Unintended perioperative hypothermia. Ochsner J. 2011;11(3):259-270.
11. Ng SF, Oo CS, Loh KH, Lim PY, Chan YH, Ong BC. A comparative study of three warming interventions to determine the most effective in maintaining perioperative normothermia. Anesth Analg. 2003;96(1):171-176, table of contents.
12. Ata A, Lee J, Bestle SL, Desemone J, Stain SC. Postoperative hyperglycemia and surgical site infection in general surgery patients. Arch Surg. 2010;145(9):858-864.
13. Kao LS, Phatak UR. Glycemic control and prevention of surgical site infection. Surg Infect (Larchmt). 2013;14(5):437-444.
14. Kotagal M, Symons RG, Hirsch IB, et al. Perioperative hyperglycemia and risk of adverse events among patients with and without diabetes. Annals of surgery. 2015;261(1):97-103.
15. Silva JM, Jr., de Oliveira AM, Nogueira FA, et al. The effect of excess fluid balance on the mortality rate of surgical patients: a multicenter prospective study. Crit Care. 2013;17(6):R288.
16. Gutierrez MC, Moore PG, Liu H. Goal-directed therapy in intraoperative fluid and hemodynamic management. J Biomed Res. 2013;27(5):357-365.
17. Edmiston CE, Jr., Leaper DJ. Intra-Operative Surgical Irrigation of the Surgical Incision: What Does the Future Hold-Saline, Antibiotic Agents, or Antiseptic Agents? Surg Infect (Larchmt). 2016;17(6):656-664.
18. Hargrove R, Ridgeway S, Russell R, Norris M, Packham I, Levy B. Does pulse lavage reduce hip hemiarthroplasty infection rates? The Journal of hospital infection. 2006;62(4):446-449.
19. Nikfarjam M, Weinberg L, Fink MA, et al. Pressurized pulse irrigation with saline reduces surgical-site infections following major hepatobiliary and pancreatic surgery: randomized controlled trial. World J Surg. 2014;38(2):447-455.
20. Cervantes-Sanchez CR, Gutierrez-Vega R, Vazquez-Carpizo JA, Clark P, Athie-Gutierrez C. Syringe pressure irrigation of subdermic tissue after appendectomy to decrease the incidence of postoperative wound infection. World J Surg. 2000;24(1):38-41; discussion 41-32.
21. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method for wound control and treatment: clinical experience. Ann Plast Surg. 1997;38(6):563-576; discussion 577.
22. Ming X, Rothenburger S, Nichols MM. In vivo and in vitro antibacterial efficacy of PDS plus (polidioxanone with triclosan) suture. Surg Infect (Larchmt). 2008;9(4):451-457.
23. Storch ML, Rothenburger SJ, Jacinto G. Experimental efficacy study of coated VICRYL plus antibacterial suture in guinea pigs challenged with Staphylococcus aureus. Surg Infect (Larchmt). 2004;5(3):281-288.
24. Rothenburger S, Spangler D, Bhende S, Burkley D. In vitro antimicrobial evaluation of Coated VICRYL* Plus Antibacterial Suture (coated polyglactin 910 with triclosan) using zone of inhibition assays. Surg Infect (Larchmt). 2002;3 Suppl 1:S79-87.
25. Sadrizadeh S, Tammelin A, Nielsen PV, Holmberg S. Does a mobile laminar airflow screen reduce bacterial contamination in the operating room? A numerical study using computational fluid dynamics technique. Patient Saf Surg. 2014;8:27.
26. Vilar-Compte D, Mohar A, Sandoval S, de la Rosa M, Gordillo P, Volkow P. Surgical site infections at the National Cancer Institute in Mexico: a case-control study. Am J Infect Control. 2000;28(1):14-20.
27. Felippe WA, Werneck GL, Santoro-Lopes G. Surgical site infection among women discharged with a drain in situ after breast cancer surgery. World J Surg. 2007;31(12):2293-2299; discussion 2300-2291.
28. Dumville JC, Walter CJ, Sharp CA, Page T. Dressings for the prevention of surgical site infection. Cochrane Database Syst Rev. 2011(7):CD003091.
29. Dumville JC, Gray TA, Walter CJ, Sharp CA, Page T. Dressings for the prevention of surgical site infection. Cochrane Database Syst Rev. 2014(9):CD003091.
30. Bowater RJ, Stirling SA, Lilford RJ. Is antibiotic prophylaxis in surgery a generally effective intervention? Testing a generic hypothesis over a set of meta-analyses. Ann Surg. 2009;249(4):551-556.
31. Gomez MI, Acosta-Gnass SI, Mosqueda-Barboza L, Basualdo JA. Reduction in surgical antibiotic prophylaxis expenditure and the rate of surgical site infection by means of a protocol that controls the use of prophylaxis. Infect Control Hosp Epidemiol. 2006;27(12):1358-1365.
32. Anderson DJ, Kaye KS, Classen D, et al. Strategies to prevent surgical site infections in acute care hospitals. Infect Control Hosp Epidemiol. 2008;29 Suppl 1:S51-61.